after yesterday's oil and sparkplug change, i took the FD for a smog check and it failed. the test did not require a dyno. the results are:

Idle Emissions Test Results


RPM %CO2 %O2 | HC (PPM) | CO(%) |
Test MEAS MEAS MEAS | MAX GP MEAS | MAX GP MEAS | Result
M1: 0 MPH 759 12.3 0.3 | 100 250 494 | 1.00 2.50 4.00 | GP
M2: 0 MPH 2417 11.9 4.2 | 130 280 4 | 1.00 2.50 0.00 | Pass


i read somewhere the idle should be 800, but im getting 759 RPM on the chart. i think the car is misfiring since the car idles rough and sounds like its about to stall. there are times when the car is idling that it drops to almost below the 500 RPM mark. the second test at 2417 RPM shows a clean running engine with 4.2% O2 oxygen (stepping on accelerator lets more air in) whereas 0.3% oxygen at 759 idle (not stepping on the accelerator, not enough air?) on the test, i believe the idle can be between 700 RPM to 1100 RPM limit. so is there a way to turn the idle RPM up?

at 759 RPM idle, the HC hydro carbon is at 494 way beyond the 100 limit and 4% CO carbon monoxide. im beginning to think it might be easier to pass with the dyno instead of the idle test. yes, the HC is FOUR (4) at 2417 RPM and 494 at low RPM.

my assumptions are: the pre-cat is clogged since its been 125k miles. maybe the sparkplug wires are worn, but i can't find any local dealers or kragen that has FD wires in stock. there seems to be an exhaust leak near the turbos that might indicate a cracked exhaust manifold. also, maybe a cracked turbo housing since there is oil all over it. i was told the exhaust leak may suck in oxygen from outside air causing the O2 sensor to pick up too lean of a mixture and to dump in more gas making it run too rich resulting in high HC.

regardless, i plan to change the pre-cat and sparkplug wires. i dont think i need to change the cat since carbon monoxide levels seem to be fine at higher RPMs.

any ideas?

 

Set idle to around 950 rpm, and try again. Make sure the cat is very warm before testing.

 

how do you set it to 950 rpm?

 

dont change the precat.... get rid of that crap!

 

you can adjust the idle at the throttle body. Look for the adjustment screw.

 

Answer for your idle question: https://www.rx7club.com/showthread.p...t=idle+control

Run you car HARD before you smog it. Try and get that cat as hot as possible before you smog.

 

make sure the air pump is working and the idle is set to factory specs.